The country also has 402 kilometers (249 miles) of coastline on the Bight of Biafra, part of the Atlantic Ocean. The topography of Cameroon is varied, ranging from tropical rain forests in the south to mountainous highlands in some western central regions, and semi-arid savanna in the far north.
The Ionisphere bounces radio waves back to earth and regulates the amount of radiation that gets to the lower atmospheres. It all depends on the Sun's activity. The stratosphere is what actually protects us from the UV rays of the sun.
Unlike P waves, S waves don't move straight through the Earth. They only travel through solid material, and so are stopped at the liquid layer in the Earth's core. Unlike body waves, surface waves (also known as long waves, or simply L waves) move along the surface of the Earth. Surface waves are to blame for most of an earthquake's carnage. They move up and down the surface of the Earth, rocking the foundations of man-made structures. Surface waves are the slowest moving of all waves, which means they arrive the last.